The present invention relates to an airbag apparatus having an airbag that is deployed and inflated at a side of an occupant of a vehicle when an impact of a force greater than a predetermined value is applied to a side of the vehicle body due to a side collision.
Typically, when an impact the magnitude of which is equal to or greater than a predetermined value is applied to a side of a vehicle, an inflator, which is incorporated in an airbag, generates and injects gas into the airbag, thereby deploying and inflating the airbag. The deployed and inflated airbag is pressed against a shoulder and the lumbar region of an occupant, thereby protecting the occupant from the side impact. Accordingly, configurations for optimizing the thickness of airbags to protect vehicle occupants when airbags are deployed and inflated have been disclosed (for example, refer to Japanese Laid-Open Patent Publications No. 2003-261000 and No. 2000-289558).
Japanese Laid-Open Patent Publication No. 2003-261000 discloses a method for optimizing the thickness of a side airbag in a deployed and inflated state by means of a seam that is formed by sewing fabric sheets of the airbag to each other. On the other hand, Japanese Laid-Open Patent Publication No. 2000-289558 discloses a method for optimizing the thickness of a side airbag in a deployed and inflated state by coupling fabric sheets of the airbag with a substantially belt-like tether, which functions as a thickness limiting member.
However, according to the publication No. 2003-261000, since the fabric sheets are directly sewn to each other, it is impossible to create a sufficient distance between the fabric sheets. Thus, it is difficult to optimize the thickness of the airbag to protect an occupant. On the other hand, although the method according the publication No. 2000-289558 is capable of widening the distance between the fabric sheets with the tether, the tether needs to be prepared as a separate member from the fabric sheets and needs to be sewn to the fabric sheets in the manufacturing process of the side airbag. This increases the number of components and the manufacturing steps. As a result, the manufacturing cost is increased.